What is the role of steroids, such as dexamethasone, in the treatment of streptococcal meningitis?

Steroids in Streptococcal Meningitis

Direct Recommendation

Dexamethasone should be administered immediately in all cases of suspected or confirmed streptococcal (pneumococcal) meningitis, given 10-20 minutes before or concomitant with the first antibiotic dose, as it reduces mortality from 34% to 14% and unfavorable outcomes from 52% to 26% in pneumococcal meningitis. 1

Evidence-Based Dosing Protocol

Adults

• Dexamethasone 10 mg intravenously every 6 hours for 4 days 1, 2
• The first dose must be given 10-20 minutes before or at minimum concomitant with the first antimicrobial dose 1, 2
• Timing is absolutely critical—benefit is maximized only when given before or with antibiotics 1

Children

• Dexamethasone 0.15 mg/kg intravenously every 6 hours for 2-4 days 1, 2
• Same timing requirement: administer 10-20 minutes before or with the first antibiotic dose 1

Pathogen-Specific Evidence for Streptococcal Meningitis

Pneumococcal meningitis shows the strongest evidence for dexamethasone benefit among all bacterial meningitis pathogens. 1, 2

• In pneumococcal meningitis specifically, dexamethasone reduces mortality from 34% to 14% and unfavorable outcomes from 52% to 26% 1
• Historical controlled trials demonstrated significant mortality reduction in pneumococcal meningitis (7 of 52 deaths with dexamethasone versus 22 of 54 deaths without dexamethasone, P < 0.01) 3
• Severe hearing loss was eliminated in survivors receiving steroids (0 of 45 patients) compared to 4 of 32 patients without dexamethasone (P < 0.05) 3

Mechanism of Benefit

Dexamethasone works through multiple protective mechanisms in bacterial meningitis 1:

• Attenuates the subarachnoid space inflammatory response, which is the major contributor to morbidity and mortality 1
• Decreases cerebral edema and reduces intracranial pressure 1
• Reduces altered cerebral blood flow and cerebral vasculitis 1
• Prevents neuronal injury mediated by pro-inflammatory cytokines 1

Critical Timing Considerations

The timing of dexamethasone administration is the single most important factor determining benefit. 1, 2

• Dexamethasone must be given before or with antibiotics to prevent the inflammatory response from antibiotic-induced bacterial lysis 2
• If antibiotics have already been started, the benefit of dexamethasone is substantially reduced 1
• Do not delay dexamethasone administration while awaiting culture results—start empirically in all suspected bacterial meningitis 1, 2

Pathogen-Specific Continuation Algorithm

Start dexamethasone empirically in all suspected bacterial meningitis, then tailor based on pathogen identification: 1, 2

• Continue dexamethasone for the full 4-day course if:

  • Streptococcus pneumoniae is identified 1, 2
  • Haemophilus influenzae type b is identified 1, 2

• Discontinue dexamethasone if:

  • Listeria monocytogenes is identified (may increase mortality) 2
  • Staphylococcus aureus (including MRSA) is identified 1
  • Other organisms besides pneumococcus or H. influenzae are identified 1

Geographic and Resource Considerations

The benefit of dexamethasone is only established in high-income countries with high standards of medical care. 1, 2

• No beneficial effects of dexamethasone were identified in low-income country studies 1
• This recommendation applies to settings with access to appropriate antibiotics, intensive care, and monitoring capabilities 1, 2

Common Pitfalls to Avoid

Do not withhold dexamethasone due to concerns about antibiotic penetration into the CSF. 1

• While dexamethasone may theoretically decrease CSF antibiotic concentrations, the overall clinical benefit outweighs this concern when appropriate antibiotics are used 1
• The dramatic mortality reduction (from 34% to 14%) in pneumococcal meningitis demonstrates that clinical outcomes are superior despite any theoretical reduction in antibiotic penetration 1

Do not delay dexamethasone while awaiting lumbar puncture or culture results. 1, 2

• Start empirically in all suspected bacterial meningitis cases 1, 2
• Adjust therapy once pathogen is identified using the algorithm above 1

Adverse Effects Profile

Adverse events are not significantly increased with dexamethasone use in bacterial meningitis 4

• One study noted increased secondary fever, gastrointestinal bleeding, and psychiatric manifestations in the dexamethasone group, but neurological complications and hearing loss were significantly reduced 5
• The benefit-to-risk ratio strongly favors dexamethasone use in pneumococcal meningitis 1, 2, 4